On Sep 30, 2006, melody from Benton, KY (Zone 7a) wrote:
These caterpilars are known for defoliating groves of sycamore trees. Not usually harmful to solitary trees, or nursery stock, but can do quite a bit of damage in the wild.
The moths are small, pale yellow with darker forewings. They emerge in early spring and lay the first generation of eggs in May, the second generation of caterpillars will pupate in late Sept/Oct, just before frost.